import React, { Component } from "react";
import Square from "../Square/Square";
export class Board extends Component {
  constructor(props) {
    super(props);
    this.state = {
      squares: [].fill(null),
      xIsNext: true,
      history:[],
    };
  }

  calculateWinner(squares) {
    const lines = [
      [0, 1, 2],
      [3, 4, 5],
      [6, 7, 8],
      [0, 3, 6],
      [1, 4, 7],
      [2, 5, 8],
      [0, 4, 8],
      [2, 4, 6],
    ];
    for (let i = 0; i < lines.length; i++) {
      const [a, b, c] = lines[i];
      if (
        squares[a] &&
        squares[a] === squares[b] &&
        squares[a] === squares[c]
      ) {
        return squares[a];
      }
    }
    return null;
  }
  handleClick(i) {
    console.log(i);
    const squares = this.state.squares.slice();
    if (this.calculateWinner(squares) || squares[i]) {
      return;
    }
    squares[i] = this.state.xIsNext ? "X" : "O";
    this.state.history.push(squares)
    this.setState({ squares: squares,xIsNext:!this.state.xIsNext });
  }
  renderSquare(i) {
    return (
      <Square
        value={this.state.squares[i]}
        onClick={() => {
          this.handleClick(i);
        }}
      />
    );
  }
  lastStep(){
    console.log(this.state.history)
    let squares=this.state.history.shift()
    this.setState({squares:squares})
  }
  render() {
    const winner = this.calculateWinner(this.state.squares);
    let status = "Next player: " + (this.state.xIsNext ? "X" : "O");
    if(winner){
      status = 'Winner: ' + winner;
    }else{
      status = 'Next player: ' + (this.state.xIsNext ? 'X' : 'O');
    }
    return (
      <div>
        <div className="status">{status}</div>
        <div className="status" onClick={() => {this.lastStep()}}>上一步</div>
        <div className="board-row">
          {this.renderSquare(0)}
          {this.renderSquare(1)}
          {this.renderSquare(2)}
        </div>
        <div className="board-row">
          {this.renderSquare(3)}
          {this.renderSquare(4)}
          {this.renderSquare(5)}
        </div>
        <div className="board-row">
          {this.renderSquare(6)}
          {this.renderSquare(7)}
          {this.renderSquare(8)}
        </div>
      </div>
    );
  }
}

export default Board;
